Miss ,crack,pop.....

[wiretwister]

Looking for ideas on what the problem could be.........
Bike runs perfect until it gets hot....after 10 miles or so, at low RPM it wants to skip, miss, sputter , backfire.....nail the throttle and it will come to life.
Whats really strange is its not all the time,as in saturday I rode 60 miles it ran fine, sunday the wife an i rode 30 or so miles and it wigged out as soon as it got hot, you never know......
Last tank of gas had Seafoam, charging system is New.
Up for suggestions.......

Thanks

 

[naughtyG]

It could be worth doing the 'shotgun' and/or 'peashooter' carb cleaning procedures - do a search on those words here to find the full instructions.

However, if it only goes funny when hot, it could also be electrical, and more than likely some wiring or component problem above the motor, as that's the hot place..

 

[dannymax]

Think I'd start with the easiest first....carburetion....do the peashooter and shotgun, simple and reasonably non-invasive. If you see some change you're on the right track, if no change then move on to other possibilities.

There are links to each process in the "VMF Links" button at the top of the page.





Haha....great minds, and all that ey 'G'!! :rofl_200:

 

[SpecOps13]

Sure sounds like the low speed circuit in the carbs.. Or, could be a blocked tank vent or tip over valve... Run the bike for ??? 5 minutes and then pop the fuel cap. If you get a whoosh of air being released, The vent system is blocked...

 

[wiretwister]

It would be sweet if it was as simple as a tank vent.

 

[95spfldmax]

The problem i've been after for years sounds like yours except it did it everytime the temp went to maximum......

A Hot Surge Problem I call it.....

Where you come to a stop and after a little while it starts to "Harley"....that's to say that it would start to stumble...get a little worse.....and if the light or whatever was longer enough you'd have blip the throttle to not stall........and more often than not slip the clutch a bit to leave without stalling......

With that said and all the things I found this winter I do not yet know if the problem is gone until I start enjoying my riding season .......ANY WEEK NOW PLEASE!!!!........but I digress.....

Things I found/fixed that may be contributors (in no order of importance):

- crimp fix and sorting out charging system.

- adjusted valves
- out of spec minorly but major running improvement
- did that before last season - problem was noticably a level better
- not quite all gone though

- corrosion build-up in the high tension lead of one of my front coil
- failed to take note of which one....oops

- Adjusted float levels
- ALL were rich...2 RH slightly rich....2 LH way off!! Either way they were
WAY off from each other and I believe that to be key.....

I really hope I got it but you should probably rule out all of these for your issue....

Hope this helps.

 

[wiretwister]

Oh crap...dont jinx me with mystery issues, Whats really wierd is I can shut it off for a minute refire it....it might run fine.

I hate mystery issues !!

 

[wiretwister]

Peashooter no help, I beginning to think its not the carbs, I rode some yesterday...again ran great for 7 0r 8 miles, then acts up, I can shut it down for a minute...refire it and the problem is instantly gone,,,but its back in a mile or two.....What the crap is wrong ??

 

[gamorg02]

Peashooter no help, I beginning to think its no the carbs, I rode some yesterday...again ran great for 7 0r 8 miles, then acts up, I can shut it down fo a minute...refire it and the problem is instantly gone,,,but its back in a mile or two.....What the crap is wrong ??

almost sounds like something is building up pressure

fuel pump? fuel filter? gas tank vent hose?

 

[Rhoy Carter]

The side stand relay can make it do weird things too, thats worth checking.

 

[wiretwister]

Bike dont have a stock fuel pump...its got a inline pump, was thinking that could be the issue, I was thinking go ahead and replace with stock one.....but I hate to just throw parts at it....
Another reason I dont think its carbs, it starts with one cyl. and then another...and then.....crack ,pop, backfires thru both ends.....and hardly runs.
Pull over, turn key off....then right back on, ( let fuel pump run the 5 seconds) refire,,,WOW perfect ( what the hell )....

 

[Rollie]

" charging system is new " ......... What did you add / modify ?

 

[wiretwister]

I replaced stator and R&R, wired straight to the battery.....Charging as it should.

 

[wiretwister]

Im to the point of taking this thing to the shop ( I really dont want to do that ).
Is it possible the fuel pump or filter is the problem ?? Only problem I see with that is when it acts a fool... I can drive the piss out of it holding it wide open and it goes.........I mean 135 it will do.....back off to go slow, miss/crack/pop/ really bad.
Ive never heard of a bike acting so whacky, Ive owned alot of bikes..but never this crap.

 

[Rollie]

Check your coils / spark plug connections for corrosion and good connections . . A bad plug can / will cause your symptons .

 

[ninjaneer]

Im to the point of taking this thing to the shop ( I really dont want to do that ).
Is it possible the fuel pump or filter is the problem ?? Only problem I see with that is when it acts a fool... I can drive the piss out of it holding it wide open and it goes.........I mean 135 it will do.....back off to go slow, miss/crack/pop/ really bad.
Ive never heard of a bike acting so whacky, Ive owned alot of bikes..but never this crap.

so it starts effin up when you decelerate only?
guys, does the peashooter and/or shotgun get at the coasting enrichers?

 

[wiretwister]

No hold on.........when it starts acting crazy, it idles fine.....it might only miss a time or two or it might not want to go at all missing backfiring out both ends....but it if hold it wide open it will eventually come to life.......

Its the shut down and restart/instant run good that has me stumped as well...........
I dont wanna take it to the yamaha shop

 

[SpecOps13]

No, take it to the Yamaha shop and it may never run again... All the top experts are right here to help you..... I'm brain dead right now and have to go work on a friends R1. Your problem's gonna take some thinking....

 

[wiretwister]

I guess I will throw a fuel pump and filter at it.........How many things could it be ??

 

[SpecOps13]

wiretwister: You should look at this thread and see how much I've thrown at my 89. It'll make you laugh if not feel better.


http://www.vmaxforum.net/showthread.php?t=15009